docs: def daily_occurrences(self, dt=None, event=None):
          '''
          Returns a queryset of for instances that have any overlap with a
          particular day.
  
          * ``dt`` may be either a datetime.datetime, datetime.date object, or
            ``None``. If ``None``, default to the current day.
  
          * ``event`` can be an ``Event`` instance for further filtering.
          '''
          dt = dt or datetime.now()
          start = datetime(dt.year, dt.month, dt.day)
          end = start.replace(hour=23, minute=59, second=59)
          qs = self.filter(
              models.Q(
                  start_time__gte=start,
                  start_time__lte=end,
              ) |
              models.Q(
                  end_time__gte=start,
                  end_time__lte=end,
              ) |
              models.Q(
                  start_time__lt=start,
                  end_time__gt=end
              )
          )
  
          return qs.filter(event=event) if event else qs